It is useful to test metal equipment, e.g. automotive engines, after manufacturing them, for leaks that prevent proper operation of the engine. In order to test the engines for leaks, water is circulated in the cooling space of the engine block and hydrostatic testing is conducted. The engines are then drained for storage, shipping, and assembly. After draining, a small amount of liquid remains in recesses at the bottom of the engine, which causes the metal to corrode. It is known that a mixture of an amine and an azole will prevent corrosion of metal equipment caused by water in its liquid state. However, this mixture is not effective in preventing vapor phase corrosion, which occurs by the further evaporation of water after the hydrostatic test water is drained from the engine block. Thus, there is a need to prevent vapor phase corrosion in such equipment, particularly where the equipment contains recesses where water can reside and evaporate.
All citations referred to under this description of the “Related Art” and in the “Detailed Description” of the invention are expressly incorporated by reference.